Browne's career in journalism began when he was drafted into the U.S. Army during the Korean War.[4][5][6] He was assigned to the Pacific edition of the Stars and Stripes, where he worked for two years. He worked for the Middletown Times Herald-Record,[7] then joined the Associated Press (AP). He worked in Baltimore from 1959 until 1961, at which point he was made chief correspondent for Indochina. On June 11, 1963, he took his famous photographs of the death of Thích Quảng Đức, a Vietnamese Mahayana Buddhist monk who burned himself to death at a busy road intersection in Saigon, in protest against the persecution of Buddhists by the South Vietnamese government led by Ngô Đình Diệm. He won a Pulitzer Prize for International Reporting[8] and received many job offers, eventually leaving the AP in 1965.

Browne worked for ABC TV for about a year but became dissatisfied with television journalism,[1] and worked freelance for several years. He did a year's fellowship at Columbia University with the Council on Foreign Relations. In 1968, he joined The New York Times, becoming its correspondent for South America in 1972. Having worked as a chemist prior to becoming a journalist,[4] in 1977 Browne became a science writer, serving as a senior editor for Discover. He returned to the Times in 1985, and went on to cover the Persian Gulf War in 1991.